991 research outputs found

    Characterization of soil heavy metal pools in paddy fields in Taiwan: chemical extraction and solid-solution partitioning

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    Ongoing industrialization has resulted in an accumulation of metals like Cd, Cu, Cr, Ni, Zn, and Pb in paddy fields across Southeast Asia. Risks of metals in soils depend on soil properties and the availability of metals in soil. At present, however, limited information is available on how to measure or predict the directly available fraction of metals in paddy soils. Here, the distribution of Cd, Cu, Cr, Ni, Zn, and Pb in 19 paddy fields among the total, reactive, and directly available pools was measured using recently developed concepts for aerated soils. Solid-solution partitioning models have been derived to predict the directly available metal pool. Such models are proven to be useful for risk assessment and to derive soil quality standards for aerated soils. Soil samples (0-25 cm) were taken from 19 paddy fields from five different communities in Taiwan in 2005 and 2006. Each field was subdivided into 60 to 108 plots resulting in a database of approximately 3,200 individual soil samples. Total (Aqua Regia (AR)), reactive (0.43 M HNO3, 0.1 M HCl, and 0.05 M EDTA), and directly available metal pools (0.01 M CaCl2) were determined. Solid-solution partitioning models were derived by multiple linear regressions using an extended Freundlich equation using the reactive metal pool, pH, and the cation exchange capacity (CEC). The influence of Zn on metal partitioning and differences between both sampling events (May/November) were evaluated. Total metals contents range from background levels to levels in excess of current soil quality standards for arable land. Between 3% (Cr) and 30% (Cd) of all samples exceed present soil quality standards based on extraction with AR. Total metal levels decreased with an increasing distance from the irrigation water inlet. The reactive metal pool relative to the total metal content is increased in the order C

    Study on the Activity of PI3K/AKT, Death Receptor and 14-3-3 Mediated Signaling Pathways Regulating Hepatocyte Apoptosis during Rat Liver Regeneration

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    Studies have shown that apoptosis is closely related to the rat liver regeneration. To understand the mechanism of hepatocyte apoptosis during rat liver regeneration at the gene transcription level, the Rat Genome 230 2.0 Array was used to determine the expression changes of genes. Then the genes associated with cell apoptosis were searched by GO and NCBI databases, and cell apoptosis signaling pathways were searched by the database of QIAGEN and KEGG. Their signaling activities were calculated by spectral function E(t). The mechanism of hepatocyte apoptosis during rat liver regeneration was analyzed by Ingenuity Pathway Analysis 9.0 (IPA). The results showed that among the 27 signaling pathways regulating cell apoptosis, the E(t) values of Apoptosis signaling pathway and 14-3-3 mediated signaling pathway were significantly increased in the progression phase (6-72h after PH) of rat liver regeneration, and the E(t) values of hepatocyte apoptosis mediated by mitochondria rout were also significantly increased. The E(t) values of death receptor signaling pathway and PI3K/AKT branch of 14-3-3 mediated signaling pathway were significantly increased in the progression phase and the terminal phase (72-168h after PH) of rat liver regeneration, and the E(t) values of hepatocyte apoptosis mediated by cytomembrane route and nucleus route were also significantly increased. Conclusion: PI3K/AKT, death receptor and mitochondria branch played a key role in promoting cell apoptosis during rat liver regeneration

    Theoretical and experimental investigations on conformal polishing of microstructured surfaces

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    Microstructured surfaces play a pivotal role in various fields, notably in lighting, diffuser devices, and imaging systems. The performance of these components is intricately related to the accuracy of their shapes and the quality of their surfaces. Although current precision machining technologies are capable of achieving conformal shapes, the post-machining surface quality often remains uncertain. To appropriately address this challenge, this paper introduces a novel conformal polishing methodology, specifically designed to enhance the surface quality of microstructured surfaces while maintaining their shape accuracy. As part of the investigations, specialized tools, namely the damping tool and profiling damping tool, are methodically developed for polishing rectangular and cylindrical surfaces. A shape evolution model is established based on the simulation of individual microstructures, incorporating the concept of finite-slip on the microstructured surface. The findings reveal that principal stresses and velocities experience abrupt variations at the convex and concave corners of rectangular surfaces as well as at the ends of cylindrical surfaces. The numerically predicted surface shape errors after polishing demonstrate reasonably good agreement with experimental results such that their discrepancies are less than 1 μm. Additionally, this method is able to successfully eradicate pre-machining imperfections such as residual tool marks and burrs on the microstructured surfaces. The arithmetic roughness (Ra) of the rectangular surface is measured to be an impressively low 0.4 nm, whereas the cylindrical surface exhibits Ra = 6.2 nm. These results clearly emphasize the effectiveness of the conformal polishing method in achieving high-quality surface finishes

    Responses of chemical composition, amino acid and fatty acid profiles of breast muscle to dietary crude fibre levels in China Micro-Ducks

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    The effects of dietary crude fibre (CF) levels on the chemical composition, amino acid (AA) and fatty acid (FA) profiles of breast muscle in male China Micro-ducks (21 - 56 d) were investigated in this study. The birds were randomly allocated to four treatments, of which dietary CF levels were 16.7, 42.6, 77.9 and 101.6 g/kg of dry matter (DM), respectively. No influences on the proportions of crude ash, crude protein, lysine, methionine, threonine, phenylalanine, histidine, arginine, aspartic acid, glutamic acid, glycine, alanine, serine, cysteine, tyrosine, proline, C12:0, C18:0, C18:1n9, C20:0 and C22:1n9 in muscle were observed across the treatments. Consequently, the concentrations of semi-essential AA, non-essential AA, total AA, aromatic AA and delicious AA in muscle, along with the Δ-9-desaturase (18) index, were not affected by the treatments. Significant lower concentrations of valine, leucine, isoleucine, essential AA, branched-chain AA, C16:1n7 and monounsaturated FA in muscle, along with a lower ratio of branched-chain to aromatic AA, were noted in a dietary treatment with a CF level of 16.7 g/kg DM compared to other dietary treatments. The rise of the dietary CF level significantly increased the proportions of DM, ether extract, gross energy, C18:2n6, C18:3n3, C20:4n6, unsaturated FA, total FA, polyunsaturated FA, n-3 polyunsaturated FA, n-6 polyunsaturated FA, essential FA, and the Δ-9-desaturase (16) index. Furthermore, the rise of the dietary CF level increased the ratios of unsaturated to saturated FA, polyunsaturated to saturated FA, and n-6 to n-3 polyunsaturated FA in muscle. However, it decreased the atherogenic index and the proportions of C14:0, C16:0, and saturated FA significantly. In conclusion, depending largely on dietary levels, CF profoundly and positively influenced the nutritional quality of breast muscle, especially the FA profile.Keywords: China Micro-duck, dietary fibre, fatty acid, nutritional quality of meat, fatty aci

    The Intrinsic Dimensionality of Attractiveness: A Study in Face Profiles

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    The study of human attractiveness with pattern analysis techniques is an emerging research field. One still largely unresolved problem is which are the facial features relevant to attractiveness, how they combine together, and the number of independent parameters required for describing and identifying harmonious faces. In this paper, we present a first study about this problem, applied to face profiles. First, according to several empirical results, we hypothesize the existence of two well separated manifolds of attractive and unattractive face profiles. Then, we analyze with manifold learning techniques their intrinsic dimensionality. Finally, we show that the profile data can be reduced, with various techniques, to the intrinsic dimensions, largely without loosing their ability to discriminate between attractive and unattractive face

    Study on the Activity of PI3K/AKT, Death Receptor and 14-3-3 Mediated Signaling Pathways Regulating Hepatocyte Apoptosis during Rat Liver Regeneration

    Get PDF
    Studies have shown that apoptosis is closely related to the rat liver regeneration. To understand the mechanism of hepatocyte apoptosis during rat liver regeneration at the gene transcription level, the Rat Genome 230 2.0 Array was used to determine the expression changes of genes. Then the genes associated with cell apoptosis were searched by GO and NCBI databases, and cell apoptosis signaling pathways were searched by the database of QIAGEN and KEGG. Their signaling activities were calculated by spectral function E(t). The mechanism of hepatocyte apoptosis during rat liver regeneration was analyzed by Ingenuity Pathway Analysis 9.0 (IPA). The results showed that among the 27 signaling pathways regulating cell apoptosis, the E(t) values of Apoptosis signaling pathway and 14-3-3 mediated signaling pathway were significantly increased in the progression phase (6-72h after PH) of rat liver regeneration, and the E(t) values of hepatocyte apoptosis mediated by mitochondria rout were also significantly increased. The E(t) values of death receptor signaling pathway and PI3K/AKT branch of 14-3-3 mediated signaling pathway were significantly increased in the progression phase and the terminal phase (72-168h after PH) of rat liver regeneration, and the E(t) values of hepatocyte apoptosis mediated by cytomembrane route and nucleus route were also significantly increased. Conclusion: PI3K/AKT, death receptor and mitochondria branch played a key role in promoting cell apoptosis during rat liver regeneration

    Spin Glasses on Thin Graphs

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    In a recent paper we found strong evidence from simulations that the Isingantiferromagnet on ``thin'' random graphs - Feynman diagrams - displayed amean-field spin glass transition. The intrinsic interest of considering such random graphs is that they give mean field results without long range interactions or the drawbacks, arising from boundary problems, of the Bethe lattice. In this paper we reprise the saddle point calculations for the Ising and Potts ferromagnet, antiferromagnet and spin glass on Feynman diagrams. We use standard results from bifurcation theory that enable us to treat an arbitrary number of replicas and any quenched bond distribution. We note the agreement between the ferromagnetic and spin glass transition temperatures thus calculated and those derived by analogy with the Bethe lattice, or in previous replica calculations. We then investigate numerically spin glasses with a plus or minus J bond distribution for the Ising and Q=3,4,10,50 state Potts models, paying particular attention to the independence of the spin glass transition from the fraction of positive and negative bonds in the Ising case and the qualitative form of the overlap distribution in all the models. The parallels with infinite range spin glass models in both the analytical calculations and simulations are pointed out.Comment: 13 pages of LaTex and 11 postscript figures bundled together with uufiles. Discussion of first order transitions for three or more replicas included and similarity to Ising replica magnet pointed out. Some additional reference

    Tree method for quantum vortex dynamics

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    We present a numerical method to compute the evolution of vortex filaments in superfluid helium. The method is based on a tree algorithm which considerably speeds up the calculation of Biot-Savart integrals. We show that the computational cost scales as Nlog{(N) rather than N squared, where NN is the number of discretization points. We test the method and its properties for a variety of vortex configurations, ranging from simple vortex rings to a counterflow vortex tangle, and compare results against the Local Induction Approximation and the exact Biot-Savart law.Comment: 12 pages, 10 figure

    The sensitivity of the vortex filament method to different reconnection models

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    We present a detailed analysis on the effect of using different algorithms to model the reconnection of vortices in quantum turbulence, using the thin-filament approach. We examine differences between four main algorithms for the case of turbulence driven by a counterflow. In calculating the velocity field we use both the local induction approximation (LIA) and the full Biot-Savart integral. We show that results of Biot-Savart simulations are not sensitive to the particular reconnection method used, but LIA results are.Comment: 9 pages, 9 figure

    Entanglement Transfer via XXZ Heisenberg chain with DM Interaction

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    The role of spin-orbit interaction, arises from the Dzyaloshinski-Moriya anisotropic antisymmetric interaction, on the entanglement transfer via an antiferromagnetic XXZ Heisenberg chain is investigated. From symmetrical point of view, the XXZ Hamiltonian with Dzyaloshinski-Moriya interaction can be replaced by a modified XXZ Hamiltonian which is defined by a new exchange coupling constant and rotated Pauli operators. The modified coupling constant and the angle of rotations are depend on the strength of Dzyaloshinski-Moriya interaction. In this paper we study the dynamical behavior of the entanglement propagation through a system which is consist of a pair of maximally entangled spins coupled to one end of the chain. The calculations are performed for the ground state and the thermal state of the chain, separately. In both cases the presence of this anisotropic interaction make our channel more efficient, such that the speed of transmission and the amount of the entanglement are improved as this interaction is switched on. We show that for large values of the strength of this interaction a large family of XXZ chains becomes efficient quantum channels, for whole values of an isotropy parameter in the region 2Δ2-2 \leq \Delta \leq 2.Comment: 21 pages, 9 figure
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